libgo: update configure.ac to upstream GCC

The libgo/configure.ac file in upstream GCC was changed in

https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=6a6d3817afa02bbcd2388c8e005da6faf88932f1

This adds an automake conditional that is not used, but will be used
in the future when and if libgo is ported to Darwin.

This CL makes the corresponding change in this repo.

Change-Id: Ieac8e85620993b1d3b55a89bbb61047e6ff9031f
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/546435
Reviewed-by: Cherry Mui <[email protected]>
Reviewed-by: Than McIntosh <[email protected]>

Author: ianlancetaylor

Diff for: libgo/configure

@@ -709,6 +709,8 @@ glibgo_toolexecdir
 WERROR
 WARN_FLAGS
 CC_FOR_BUILD
+ENABLE_DARWIN_AT_RPATH_FALSE
+ENABLE_DARWIN_AT_RPATH_TRUE
 enable_static
 enable_shared
 CPP
@@ -11545,7 +11547,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11548 "configure"
+#line 11550 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -11651,7 +11653,7 @@ else
   lt_dlunknown=0; lt_dlno_uscore=1; lt_dlneed_uscore=2
   lt_status=$lt_dlunknown
   cat > conftest.$ac_ext <<_LT_EOF
-#line 11654 "configure"
+#line 11656 "configure"
 #include "confdefs.h"
 
 #if HAVE_DLFCN_H
@@ -13780,6 +13782,14 @@ CC="$lt_save_CC"
 
 
 
+ if test x$enable_darwin_at_rpath = xyes; then
+  ENABLE_DARWIN_AT_RPATH_TRUE=
+  ENABLE_DARWIN_AT_RPATH_FALSE='#'
+else
+  ENABLE_DARWIN_AT_RPATH_TRUE='#'
+  ENABLE_DARWIN_AT_RPATH_FALSE=
+fi
+
 
 CC_FOR_BUILD=${CC_FOR_BUILD:-gcc}
 
@@ -14399,6 +14409,7 @@ esac
 
   test -z "$HWCAP_CFLAGS" && HWCAP_CFLAGS=''
 
+
   # Restrict the test to Solaris, other assemblers (e.g. AIX as) have -nH
   # with a different meaning.
   case ${target_os} in
@@ -16389,6 +16400,10 @@ if test -z "${MAINTAINER_MODE_TRUE}" && test -z "${MAINTAINER_MODE_FALSE}"; then
   as_fn_error $? "conditional \"MAINTAINER_MODE\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi
+if test -z "${ENABLE_DARWIN_AT_RPATH_TRUE}" && test -z "${ENABLE_DARWIN_AT_RPATH_FALSE}"; then
+  as_fn_error $? "conditional \"ENABLE_DARWIN_AT_RPATH\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
 if test -z "${USE_LIBFFI_TRUE}" && test -z "${USE_LIBFFI_FALSE}"; then
   as_fn_error $? "conditional \"USE_LIBFFI\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5

Diff for: libgo/configure.ac

@@ -53,6 +53,7 @@ AC_LIBTOOL_DLOPEN
 AM_PROG_LIBTOOL
 AC_SUBST(enable_shared)
 AC_SUBST(enable_static)
+AM_CONDITIONAL([ENABLE_DARWIN_AT_RPATH], [test x$enable_darwin_at_rpath = xyes])
 
 CC_FOR_BUILD=${CC_FOR_BUILD:-gcc}
 AC_SUBST(CC_FOR_BUILD)